In drive trains of motor vehicles, due to cost reasons a direct measurement of instantaneously generated drive torques is usually not provided. Because an electronic gas pedal is used, no mechanical connection to the drive unit is present. However, unintended torque or power outputs of the drive unit may result in the event of software errors or, for example, due to disturbances in the signal transmission between the gas pedal and the control unit which controls the drive unit and which receives the setpoint torque intended by the driver and relays same to the drive unit. In particular in hybrid, hydraulic, or electric vehicles, even for a stationary vehicle a frictional connection may be present between a drive unit and the drive wheels. This undesirable torque or power output of a drive unit, for example due to an error in the data communication or a component defect, may cause a safety-critical movement of the vehicle without this being wanted by the driver.
Such unintended torque or power outputs occur not only in hybrid, electric, or hydraulic vehicles, but also in vehicles having a conventional internal combustion engine drive, and must therefore be monitored in such vehicles as well.